From 985569b5dd253d1c27b05c719f26f2a7a08b085a Mon Sep 17 00:00:00 2001
From: Stefan Bueringer <sbueringer@gmail.com>
Date: Sat, 22 Jul 2023 09:08:26 +0200
Subject: [PATCH] builder: return error when multiple reconcilers are set

---
 pkg/builder/controller.go      | 3 +++
 pkg/builder/controller_test.go | 6 +++---
 2 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/pkg/builder/controller.go b/pkg/builder/controller.go
index 570cfd63d0..2bcb9b0de9 100644
--- a/pkg/builder/controller.go
+++ b/pkg/builder/controller.go
@@ -344,6 +344,9 @@ func (blder *Builder) doController(r reconcile.Reconciler) error {
 	globalOpts := blder.mgr.GetControllerOptions()
 
 	ctrlOptions := blder.ctrlOptions
+	if ctrlOptions.Reconciler != nil && r != nil {
+		return errors.New("reconciler was set via WithOptions() and via Build() or Complete()")
+	}
 	if ctrlOptions.Reconciler == nil {
 		ctrlOptions.Reconciler = r
 	}
diff --git a/pkg/builder/controller_test.go b/pkg/builder/controller_test.go
index dd98c2e565..ff734abd83 100644
--- a/pkg/builder/controller_test.go
+++ b/pkg/builder/controller_test.go
@@ -298,7 +298,7 @@ var _ = Describe("application", func() {
 			Expect(instance).NotTo(BeNil())
 		})
 
-		It("should prefer reconciler from options during creation of controller", func() {
+		It("should not allow multiple reconcilers during creation of controller", func() {
 			newController = func(name string, mgr manager.Manager, options controller.Options) (controller.Controller, error) {
 				if options.Reconciler != (typedNoop{}) {
 					return nil, fmt.Errorf("Custom reconciler expected %T but found %T", typedNoop{}, options.Reconciler)
@@ -315,8 +315,8 @@ var _ = Describe("application", func() {
 				Owns(&appsv1.ReplicaSet{}).
 				WithOptions(controller.Options{Reconciler: typedNoop{}}).
 				Build(noop)
-			Expect(err).NotTo(HaveOccurred())
-			Expect(instance).NotTo(BeNil())
+			Expect(err).To(HaveOccurred())
+			Expect(instance).To(BeNil())
 		})
 
 		It("should allow multiple controllers for the same kind", func() {